Levo-carnitine, its derivatives, and free fatty acids in serum, heart, liver, and muscle of both tumoral and alcoholic rats.

We present a comparative study of carnitine-related fatty acid metabolism in rats bearing a Yoshida sarcoma, in chronic alcoholic rats, and in control rats. Levels of levo-carnitine, acetylcarnitine, acylcarnitine, and free fatty acids were studied in serum and in different tissues--liver, heart, and skeletal muscle--of each group of rats. Chronic alcoholic rats showed high levels of free fatty acids and elevated levo-carnitine and acetylcarnitine levels relative to those of the controls. Biosynthesis of carnitine appeared to be increased, whereas fatty acid oxidation was depressed. Tumor-bearing rats also showed high levels of free fatty acids in both serum and tissues. However, levels of levo-carnitine were decreased in this group. It seems that the tumor not only utilizes the precursors of carnitine biosynthesis but also increases carnitine expenditure.